Certain treatments require the temporary or permanent interruption or modification of select nerve function. One example treatment is renal nerve ablation, which is sometimes used to treat conditions related to congestive heart failure or hypertension. The kidneys produce a sympathetic response to congestive heart failure, which, among other effects, increases the undesired retention of water and/or sodium. Ablating some of the nerves running to the kidneys may reduce or eliminate this sympathetic function, which may provide a corresponding reduction in the associated undesired symptoms.
Many nerves, including renal nerves, run along the walls of or in close proximity to blood vessels and thus can be accessed via the blood vessels. In some instances, it may be desirable to ablate perivascular renal nerves using ultrasound energy. The target nerves must be heated sufficiently to make them nonfunctional, but heating tissues can cause significant pain during the procedure. Pain relief during renal nerve ablation has been addressed by medication, which does not always control the pain adequately. It may be desirable to provide for alternative systems and methods for intravascular nerve modulation and pain management during the nerve modulation.